Don Godke's Downdraft mounts inside the chamber, on new longer Stainless Steel hardware, I provide, that replaces existing Chimney hardware (except Yoder, which mounts differently).
The smoke & air, which is heated & higher pressure is racing to get to the cooler lower pressure outside the chimney, but is forced to grate level or lower, entering the opening in the Downdraft at the bottom.
The Downdraft helps hold more heat & smoke in the chamber, longer.
It helps reduce pellet consumption, therefore paying for itself in no time.
The Downdraft helps even temperatures across the grill.
My Downdraft helps provide a quicker startup to temperature.
Here is a news story our local NBC affiliate station KWQC TV-6 Fran Riley's Feature Story did on Don Godke's Downdraft:
Here is a video overview Ken Fisher created, showing the installation and features:
A Users video: